Yesterday evening, Pfizer and Johnson & Johnson announced the failure of a second Phase III trial of bapineuzumab, an anti-amyloid antibody known as “bapi,” for the treatment of Alzheimer’s disease. The R&D syndicate, which also includes Elan, will abandon further development of intravenous formulations of the drug, although two small Phase 2 studies evaluating subcutaneous delivery will continue. Data on subcutaneous bapi won’t be available until early 2014. I expect those studies will fail too.

For nearly five years, I have been a vocal critic of the amyloid hypothesis, which posits that the buildup of amyloid “plaques” in the brain cause the progressive cognitive and functional decline that is the hallmark of Alzheimer’s disease. Amyloid bulls — nearly ubiquitous in early 2008 but still present, albeit in smaller numbers — usually respond by citing a few supportive hints, such as the early-onset, Alzheimer-like neuropathological changes observed in amyloid plaque-prone Down’s syndrome patients.

For years, amyloid optimism has required dismissing or minimizing the lessons of history. Bapi is only the most recent addition to the graveyard of amyloid beta-clearing drugs that have failed in prospective, randomized clinical trials. Other notable blowups include Elan’s AN1792, Axonyx’ phenserine, Myriad Genetics’ Flurizan, and Eli Lilly’s semagacestat. Once Eli Lilly’s solanezumab — an antibody similar to bapi — fails later this year, we will have data from six major Phase III trials without even a shred of support for the amyloid hypothesis. That’s hard to ignore.

My inaugural Forbes column used bapi as a proxy to examine the excessive optimism that permeates the healthcare industry. Today, let’s look at a few lessons we can learn from this mess and questions I think must be answered before moving additional anti-amyloid drugs into late-stage trials.

1. Post hoc justifications for Phase III trials are insufficient.

Rather than conduct a series of massive pivotal trials that likely cost $400 million or more, Pfizer and Johnson & Johnson should have prospectively tested any post hoc hypotheses generated from Elan’s failed Phase II in additional Phase II studies. Let’s hope bapi’s failure raises the bar going forward. Evidence to support pivotal trials of any future anti-amyloid drug candidates should be consistent across subgroups and prospectively defined. R&D dollars are precious and should not be wasted on wishful thinking.

2. The pathological-clinical disconnect in Alzheimer’s disease must be explained.

Amyloid bulls often excuse the failures of the past by suggesting that clinically mild-to-moderate Alzheimer’s patients are “too far gone” for an anti-amyloid drug to have an impact. This doesn’t make sense. If amyloid is the critical toxic component and study patients are at an early stage clinically, an effective anti-amyloid therapy should slow disease progression. The “too far gone” thesis also ignores the results of a 2008 Lancet case report form Elan’s failed Phase I trial of AN1792, an anti-amyloid vaccine. The authors’ post-autopsy conclusion is unambiguous: “Although immunization … resulted in clearance of amyloid plaques … this clearance did not prevent progressive [clinical] neurodegeneration.” If the amyloid thesis is correct, scientists should be able to show how subclinical pathological changes relate to frank clinical progression.

3. We need more sensitive diagnostics.

I often hear that our clinical tests for Alzheimer’s — the cognition-focused ADAS-cog and activities of daily living-based Disability Assessment for Dementia, or DAD — are too crude to detect patients at an early stage of disease. That may be true, but the complaint often seems to hinge on the unexplained lag between hidden pathological and inexorable clinical changes. I agree that we need to develop better tests, but that’s hard to do when we don’t know what we should be looking for.

Hopefully, bapi’s failure will serve as a wake up call for the scientific and investment community. Until we understand the basic science of Alzheimer’s disease, we will not find a meaningful therapeutic solution. Let’s redirect R&D resources towards improving our grasp of basic Alzheimer’s biology before we throw more Phase III spaghetti at the wall in the hope that something sticks.

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Not really sure what to make of your commentary. On the one-hand, I wholeheartedly agree we need more sensitive diagnostics for Alzheimer’s disease (and many other diseases for that matter).

On the other hand, your implicit criticism of the science directed at trying to identify treatments seems unfounded. My general sense is you don’t understand the scientific method: a hypothesis is developed, experiments are designed and conducted, and the findings are tested for statistical significance. That is what Pfizer/J&J did. That is what other organizations testing amyloid drugs are doing. And that is what anyone testing other forms of intervention will be expected to do. In this regard, negative results are informative, albeit disappointing.

But I’m more troubled by your presentation of the science. You seem to favor sweeping generalities that are unsupported and not subject to nearly the same scrutiny that the studies you criticize were subjected to.

For example, you write, “Pfizer and Johnson & Johnson should have prospectively tested any post hoc hypotheses generated from Elan’s failed Phase II in additional Phase II studies.” Well that sounds awfully nice, but what studies are you proposing? What statistics and sample sizes do you offer? Might Pfizer and J&J, considered this but rejected it in favor of the studies they did pursue? And how would the endpoints of these hypothetical studies have made you feel better in either supporting or rejecting the amyloid hypothesis?

It is easy to play armchair quarterback and propose vague alternatives, but without detail they are not options of substance. You simply have a ‘gut instinct’ that you disagree.

You also note “Amyloid bulls often excuse the failures of the past by suggesting that clinically mild-to-moderate Alzheimer’s patients are “too far gone” for an anti-amyloid drug to have an impact. This doesn’t make sense.” (I’ll limit my arguments to these two points, since you only offer these two points in your arguments). Not true. You’ve heard of “downstream changes”? What that means is that once certain ‘upsteam events’ occur, downstream changes take place which become important in a disease state. They take over. For example, cancer acquiring a metastatic capaility. While the intial transformation of a cell is the primary oncologic event, it is the acquistion of metastatic traits that becomes important in the ultimate clinical signifance of cancer. That is why is it so important to catch cancer before it spreads.

This may be true for Alzheimer’s disease as well. As amyloid burden increases, downstream changes may take place (for example neuronal cell death, synaptic dysfunction) which ultimately become the more important manifestation of the disease, but would not have occured without the initial pathology in amyloid levels. So it is not far-fetched at all to conceive that amyloid could be trigger for Alzheimer’s which, once passing certain levels, leads to downstream changes that are today insurmountable.

Then again, this may not be the case at all. But the point is to leave it to the scientific method to test these hypothesis in a rigorous manner. Let’s not have valid potential causes of challenging diseases accepted or rejected on the basis of bulls or bears of the stock market.

there has to be minimal requirements before spending billions in testing weak hypotheses. Prior data was very weak. Nathan is right and i believe the scientific community would benefit from external scrutiny. Even if you believe everyone else is stupid

First, a question: do you think that Pfizer/J&J did not have minimal requirements before they undertook the bapi Phase 3 study?

Second, a comment: the prior data on bapi from Elan may have failed, but that doesn’t mean the amyloid hypothesis is incorrect. It doesn’t even mean the drug doesn’t work. Incorporating the learning from prior clinical trials whether failed or successful can improve the outcome of subsequent studies (the history of drug development is replete with these exmaples).

Third, a clarification: I don’t believe everyone else is stupid by any means; what I was suggesting is that we use the scientific method and statitistical analysis to determine whether a drug does or does not work, or whether a hypothesis is or is not correct, not ‘intuition’. In this case, the scientific method showed bapi did not work under these conditions. Case closed. But don’t throw the baby out with the bathwater on that basis alone.

Sir – your credentials on amyloid theory?? Skeptic?? “Critical thinker”??? I’m sorry, where does it say accomplished research scientist? You’ve been a “vocal critic of the amyloid hypothesis for 5 years”?? Impressive! I know research scientists who have been skeptics of self proclaimed ‘professional healthcare investor’ for years, and Wall Street proved them right…

I have a father with advanced Alzheimer’s disease. He no longer can clean himself, care for himself, or conduct an intelligent conversation. Ask his daughter, or anyone with an Alzheimer’s relative, if they think this was senseless optimism. We pray everyday that a company would make investments in what they deem to be promising products. They are in a much better position to make those decisions than an analyst.

But then, I forgot, you are a critical thinker. You probably have a cure all mapped out. Keep us posted, Karnac.

Whilst i am not surprised at these results, I tend to also take the view that the most complex part of the body to research is the brain. Many many neuroscience drugs fail at phase 3. In fact Prozac failed several phase 3 trials if I am correct. I don’t think you are correct through … I have no doubt plaque on the brain or some sort of interruption of nerve signalling has a part to play but as the brain is very complicated it may take more than removing or delaying plaque build up to improve Alzeimer function.

I think Nathan’s criticism regarding Pfizer and J&J is valid, even though it is their shareholder’s money they burn. How come that analysts gave the phase 3 trial a 40% of success rate? R&D execs rushed into the phase 3 trial without carefully considering the lessons of failed trials. Some admitted it even in press releases. The problem seems to be that some big pharma execs are so much under pressure that they still are on the hunt for the one drug that cures all Alzheimer’s disease. AD might be better understood as a collection of different diseases, well that demands more creative thinking on the pharma executives part, as the market appears to be smaller. Some pharma companies have learned the lesson (Novartis appears to be among the smarter ones) and integrate orphan disease strategies in their thinking.

These bapi failures costed so much, that we have to be fearful that companies will stay away from Alzheimer’s disease in the future. That is where big pharma R&D strategies like Pfizer’s really hurt patients.

The armchair quarterback argument is valid, as it is always easier to criticize when you’re not in charge and being in charge of R&D means operating in uncertain territory. To his credit, Nathan was always an outspoken critic of the bapi approach. However, history shows, some big pharma execs prefer rather to withdraw than learn. Just look at Pfizer after the self inflicted 2006 torcetrapib disaster.

How pharma companies handle these failures tells a lot about their corporate culture, and frankly more so how big pharma gets into these disasters at the first place. People like Nathan relentlessly help us understand that. I am missing John LaMattina’s self criticism, at least there were some good consequences as he had to “retire” from Pfizer after his torcetrapib failure.

I think Nathan’s criticism regarding Pfizer and J&J is valid, even though it is their shareholder’s money they burn. How come that analysts gave the phase 3 trial a 40% of success rate? R&D execs rushed into the phase 3 trial without carefully considering the lessons of failed trials. Some admitted it even in press releases. The problem seems to be that some big pharma execs are so much under pressure that they still are on the hunt for the one drug that cures all Alzheimer’s disease. AD might be better understood as a collection of different diseases, well that demands more creative thinking on the pharma executives part, as the market appears to be smaller. Some pharma companies have learned the lesson (Novartis appears to be among the smarter ones) and integrate orphan disease strategies in their thinking.

These bapi failures costed so much, that we have to be fearful that companies will stay away from Alzheimer’s disease in the future. That is where big pharma R&D strategies like Pfizer’s really hurt patients.

The armchair quarterback argument is valid, as it is always easier to criticize when you’re not in charge and being in charge of R&D means operating in uncertain territory. To his credit, Nathan was always an outspoken critic of the bapi approach. However, history shows, some big pharma execs prefer rather to withdraw than learn. Just look at Pfizer after the self inflicted 2006 torcetrapib disaster and how they discontinued even promising drug development programs.

How pharma companies handle these failures tells a lot about their corporate culture, and frankly more so how big pharma gets into these disasters at the first place. People like Nathan relentlessly help us understand that. I am missing John LaMattina’s self criticism, at least there were some good consequences as he had to “retire” from Pfizer after his torcetrapib failure.

I totally agree with all of Nathan’s comments. A group of us, including the late Mark Smith, Keith Crutcher, and George Perry (Senior Editor of the Journal of Alzheimer’s Disease) have been critical of the “amyloid hypothesis” since 2000. How could you consider attacking a brain protein without some inkling of an idea of what it is really doing. Amyloid is a normal protein, probably critical to the formation of memory, that actually goes down in the spinal fluid with the advance of the AD dementia??? Making an anti-body to amyloid is like making an anti-body to hemoglobin and expecting it to cure hemophilia. The amyloid, the plaques, and the tangles are not the cause of Alzheimer’s disease and its dementia, and they are not even in the causal chain. What we have to understand before starting any treatments is exactly how prolems with metabolism of the amyloid pre-protein (APP) lead to the pair-helical filaments that cause dementia. The amyloid plaques and neurofibrillary tangles are late side-effects of that process that are not related to the dementing mechanisms. The pathological mechanisms must be related to the APP switch at the synaptic level.

The dementia clinicians and neuropathologists had identified neuroplasticity as the critical factor to understand in the mid 1980s. However, when the amyloid protein was sequenced in 1984 from the plaques, and related genetic factors were massively introduced into mice, causing an unrelated disease called mouse-heimers, the field went down a mega-billion dollar rodent hole. With clear statements like Nathan is making, that hole can be cemented over so we can get back on track to determine what Alzheimer’s disease is and how to prevent it. The understanding of the APP switch will most likely lead to determining a successful treatment. The APP-673 location (the recent Iceland gene that prevents Alzheimer’s disease) and the APOE gene are critical clues that Nature has provided. And, prevention must occur decades before the first signs of memory problems because the Alzheimer processes are completely irreversible.

The late Mark Smith and colleagues were among the first to identify that peroxynitrite-mediated damage was widespread in Alzheimer’s disease. Subsequent studies have linked peroxynitrites to neurofibrillary tangles, to deficits in acetylcholine, and to NMDA activation resulting in the influx of calcium and the release of glutamate killing brain cells. Whatever happened to this hypothesis and why has is not gained wider acceptance? If nearly every aspect of Alzheimer’s disease can be explained directly or indirectly by peroxynitrites and every peroxynitrite scavenger has ameliorated Alzheimer’s disease in animals or human clinical trials why has it been left to wither on the vine?

Here is your answer as to what causes the processing of the amyloid precursor protein and the subsequent formation of amyloid plaques.

Various first messengers linked to phospholipase C, including acetylcholine and interleukin 1, regulate the production both of the secreted form of the amyloid protein precursor (APP) and of amyloid beta-protein. We have now identified intracellular signals which are responsible for mediating these effects. We show that activation of phospholipase C may affect APP processing by either of two pathways, one involving an increase in protein kinase C and the other an increase in cytoplasmic calcium levels. The effects of calcium on APP processing appear to be independent of protein kinase C activation. The observed effects of calcium on APP processing may be of therapeutic utility.

This article by J.D. Buxbaum and colleagues was from 1994. Through the activation of protein kinase C, phospholipase C also causes the production of superoxide anions and inducible nitric oxide which combine to form peroxynitrites. Later homocysteine levels (which increase due to amyloid plaques) contribute to the formation of peroxynitrites again through the activation of protein kinase C. This is highly frustrating for me: the mechanism for the formation of the amyloid precursor protein and amyloid plaques has been known since 1994 and the role of peroxynitrites as the likely cause of Alzheimer’s disease has been known since at least 1997. That’s fifteen years where significant progress should have been made in preventing and treating this disease and was not. It’s easier and more profitable to just keep using the drugs that already exist and let one new drug after another fail than it is to treat this disease with natural peroxynitrite scavengers that cannot be patented.

The amyloid hypothesis is not wrong, it just isn’t right. The main cause of Alzheimer’s disease is a toxin called peroxynitrites. The same pathways that lead to the formation of amyloid plaques also lead to the formation of peroxynitrites. And as part of a vicious circle peroxynitrites contribute to the aggregation of plaques and the aggreagation of plaques contributes to the formation of peroxynitrites. Remove all of the plaques and the damage done by peroxynitrites remains. Peroxynitrites oxidize and nitrate a series of transport systems, enzyme, and receptors critical for brain function, such as those involved in the production and release of acetylcholine–a neurotransmitter critical for short-term memory.

The best means to treat the disease is with compounds containing methyls which bind to peroxynirtites and phenols which scavenge peroxynitrites (converting them into a less dangerous form) and reverse part of their oxidative and nitration damage. Methyl phenols can damage the liver when taking internally, but fortunately methyl phenols (such as carvacrol, thymol, and eugenol) contained in several essential oils (bay laurel, clove, holy basil, thyme, and rosemary) can be inhaled into the hippocampus, the part of the brain most damaged by peroxynitrites. Human clinical trials using essential oils have partially reversed Alzheimer’s disease. Aromatherapy is generally safe but can increase anxiety in individuals taking anti-anxiety medications or medications for hyperthyroidism and can increase anxiety, high blood pressure, and risk of seizure in people with high levels of adrenaline (which includes a subtantial minority of people with Alzheimer’s disease). The use of more relaxing oils (such as lavender, rose, or orange), weaning people off of anti-anxiety medications, or if necessary the use of medications to lower adrenaline levels may offset these problems. Otherwise, aromatherapy is the most effective means currently available to treat Alzheimer’s disease.

The main cause of Alzheimer’s disease is actually age. Once age is accounted for, 95% of Alzheimer’s disease can be related to APOE genotype. There is another 5% of Alzheimer’s disease that is related to rare genes. However, causation is complex. The question is how many factors can we put into better balance to delay the failures in neuroplastic mechanisms that lead to Alzheimer’s disease. Some of the answers will be environmental, and we might discover some medications that will prevent Alzheimer’s disease. But, until we find something so robust as the effect on the APP-673 genetic variation, we need to explore as many of the most promising avenues as possible with very solid scientific approaches. (Gemma Casadesus Smith, Mark’s widow, is continuing his work, and she should be given the due attention that her heroic continuation of Mark’s work merits.)

Age as such is not the cause of Alzheimer’s disease, it only allows time for the real risk factors for the disease to take effect. The pathways to Alzheimer’s disease which lead to the formation of amyloid plaques and to peroxynitrites are the following. High levels of myo-inositol caused by high glucose in the brain (glucose is converted to myo-inositol in the hippocampus), high blood pressure (due to the sodium myo-inositol co-transporter), and Down syndrome (because people with Down syndrome have an extra chromosome with the sodium myo-inositol co-transporter); inhibition of the phostphatidylinositol 3 kinase by presenilin gene mutations, the APOE 4 gene, and bisphosphonate osteoporosis drugs such as Fosamax, and the activation of phospholipase C–either beta or gamma–which converts phosphatidylinositol 4,5 biphosphate into inositol 1,4,5 triphosphate by glucose, angiotensin II (a risk factor for high blood pressure), various viruses and bacteria, mercury, aluminium fluoride, and various pesticides. These are just some of the many risk factors for Alzheimer’s disease but they all act upon the same pathways.

Polyphenols in various fruits, vegetables, spices and essential oils inhibit phospholipase C gamma and the ability of both phospholipase C gamma and beta to produce peroxynitrites. Thus a diet high in polyphenols may delay the onset of the disease in some people (along with polyunsaturated fats such as fish oil which may also inhibit phospholipase C gamma).

I did not know Mark Smith but I admired his research and glad that his widow is continuing his work. I would go back to his article entitled “Widespread Peroxynitrite-Mediated Damage in Alzheimer’s Disease” (1997). This disease is partially reversible because oxidation and nitration by peroxynitrites is partially reversible and because neurons can be regenerated in the hippocampus with the use of peroxynitrite scavengers. One does not have to be a genius to figure out this disease.

The issue of age and Alzheimer’s disease is fundamental. It is well accepted that the incidence of Alzheimer’s disease doubles every 5 years between 50 and 95. This exponential rate is greater than the relationship of mortality to age and strongly supports the application of the Gompertz Law (see Wikipedia) to the development of Alzheimer’s disease, basically the progressive failure of redundant memory mechanisms (ref to Gavrilov and Gavrilova). Thus age (or time) is the fundamental factor that leads to Alzheimer’s disease, and so needs to be considered more than it has been. Specifically, age needs to be considered for its affect on the extensive systems of neuroplastic brain mechanisms, with the plaque-generating and neurofibrillary tangle-generating mechanisms at the core of the search.

The clearest clues to the Alzheimer’s disease process are genetic, and at this point, they all relate to amyloid. The failure of the amyloid hypothesis should advance the field, not lead to deterioration into flayling with a multitude of issues relating to all of the different system levels affected by age. The failure of the amyloid hypothesis is a critical scientific clue that the amyloid protein, at least by itself, is not the cause of Alzheimer’s disease. The issue of whether amyloid has to be treated at a younger age is probably misguided, though prevention of the AD process at a young age is really the only way to go. Concern that amyloid oligimers are the actual factors causing Alzheimer’s is really have much less likely than is commonly argued. However, the amyloid pre-protein (APP) is at the start of the causal chain.

The point that I am trying to make is that the whole causal chain from amyloid-related genetic factors, initiated with the genesis of the APP molecule and now including an APOE relationship to amyloid, leading to dementia needs to be understood before suggesting any new treatments. The chain does involve the beta-secretase and gamma-secretase (as evidenced by known mutations). However, the path must now be considered unlikely to involve the beta-amyloid protein itself. Now, the likely next step, following the requisite beta cleavage of the APP is the gamma cleavage, which produces both the beta-amyloid and the AICD (APP Intra Cellular Domain). The AICD protein appears to phosphorylate the tau protein, and this is a critical process involved in memory and affecting millions of synapses per second during the encoding of information. If the APP switch gets out of balance (easily possible with Down syndrome, the known genetic factors, and advancing age), an excess of AICD will lead to hyper-phosphorylation of tau, resulting in large scale dendritic strangulation, and dementia. Prevention considerations need to be redirected to this chain.

Many factors, including peroxynitrites, polyphenols, essential oils, various viruses and bacteria, mercury, aluminium, fluoride (though aluminum does have some effect on tau, and fluoride could protect against that effect), and pesticides have no clear relationship to the causal chain. The possible relationships of certain NSAIDs and statins to preventing Alzheimer’s disease are still worth considering in terms of whether they might have specific effects on gamma secretase and reduce the toxicity of the AICD. But all such factors must be studied for whether they have specific effects on the causal chain. There should be great optimism that this causal chain could be controlled, if we just focus on trying to understand the process first. This will take a whole field of geniuses (and protection from self-serving interests such as led to the megabillion and 28 year over-expenditure and narrow focus on the amyloid hypothesis).

To reiterate: Since 1994, the pathway that leads to the formation of amyloid plaques has been known (phospholipase C). Amyloid plaques are not the cause of Alzheimer’s diesase, but a contributing factor. Even if all the plaques could be removed the damage done by peroxynitrites would remain. At the very best, such a strategy would stop the progression of Alzheimer’s disease. That is why the amyloid strategy is failing.

Since the mid-1990s it has been known that peroxynitrites are a principal cause of Alzheimer’s disease.

Abstract Oxidative stress has been proposed as a pathogenetic mechanism in Alzheimer’s disease. One mechanism of oxidative damage is the nitration of tyrosine residues in proteins, mediated by peroxynitrite breakdown. Peroxynitrite, a reaction product of nitric oxide and superoxide radicals, has been implicated in N-methyl-D-aspartate receptor-mediated excitotoxic damage. Reported evidence of oxidative stress in Alzheimer’s disease includes increased iron, alterations in protective enzymes, and markers of oxidative damage to proteins and lipids. In this report, we demonstrate the presence of nitrotyrosine in neurofibrillary tangles of Alzheimer’s disease. Nitrotyrosine was not detected in controls lacking neurofibrillary tangles. Immunolabeling was demonstrated to be specific nitrotyrosine in a series of control experiments. These observations link oxidative stress with a key pathological lesion of Alzheimer’s disease, the neurofibrillary tangle, and demonstrate a pathogenetic mechanism in common with the other major neurodegenerative diseases of aging, Parkinson’s disease and amyotrophic lateral sclerosis. These findings further implicate nitric oxide expression and excitotoxicity in the pathogenesis of cell death in Alzheimer’s disease.

Abstract Increasing evidence suggests that oxidative damage to proteins and other macromolecules is a salient feature of the pathology of Alzheimer’s disease. Establishing the source of oxidants is key to understanding what role they play in the pathogenesis of Alzheimer’s disease, and one way to examine this issue is to determine which oxidants are involved in damage.

In this study, we examine whether peroxynitrite, a powerful oxidant produced from the reaction of superoxide with nitric oxide, is involved in Alzheimer’s disease. Peroxynitrite is a source of hydroxyl radical-like reactivity, and it directly oxidizes proteins and other macromolecules with resultant carbonyl formation from side-chain and peptide-bond cleavage. Although carbonyl formation is a major oxidative modification induced by peroxynitrite, nitration of tyrosine residues is an indicator of peroxynitrite involvement. In brain tissue from cases of Alzheimer’s disease, we found increased protein nitration in neurons, including but certainly not restricted to those containing neurofibrillary tangles (NFTs). Conversely, nitrotyrosine was undetectable in the cerebral cortex of age-matched control brains. This distribution is essentially identical to that of free carbonyls.

These findings provide strong evidence that peroxynitrite is involved in oxidative damage of Alzheimer’s disease. Moreover, the widespread occurrence of nitrotyrosine in neurons suggests that oxidative damage is not restricted to long-lived polymers such as NFTs, but instead reflects a generalized oxidative stress that is important in disease pathogenesis.

Peroxynitrites contribute to the hyperphosphorylation of tau proteins by oxidating g-protein coupled receptors and trysoine kinase receptors preventing protein kinase C and AKT from inactivating the enzyme GSK3 which is necessary to prevent the hyperphosphorylation of tau proteins. Furthermore, the peroxynitrite-mediated nitration of tau proteins prevent them from being reconstituted to their normal form. It is no conincidence that all neurofibrillary tangles contain nitrated tau proteins.

The use of peroxynitrite scavengers partially reverses all of these problems. Eugenol, a methoxyphenol found in various essential oils such as clove, bay laurel, cinnamon leaf, and rosemary, appears to be a particulary effective peorxynitrites scavenger (the methyl group binds to peroxynitrites and the phenol group converts it into water and a nitrogen dioxide anion).

Effects of Eugenol on the Central Nervous System: Its Possible Application to Treatment of Alzheimer’s Disease, Depression, and Parkinson’s Disease Author: Irie, Yoshifumi

Eugenol (4-allyl-2-methoxyphenol) is a fragrant compound that is commonly contained in various sorts of plants, especially in spices and medicinal herbs. Eugenol … has anticonvulsive and anti-microbial activities. Besides, anti-inflammatory and antioxidative activities of eugenol are known. A body of evidence suggests that eugenol can be used as a drug for treatment of Alzheimer’s disease (AD). According to recent reports, the extract of a medicinal plant Rhizoma Acori Graminei (RAG) alleviates neurotoxicity induced by amyloid beta peptides (Aβ) in vitro and the active constituent of RAG is eugenol. Eugenol inhibits Aβ-induced excessive influx of calcium ion into neurons that causes neuronal death. Moreover, eugenol possesses an antidepressant-like activity. Eugenol, like other antidepressants, increases expression of brain-derived neurotrophic factor (BDNF) gene in the hippocampus, which is necessary for an antidepressant to exhibit its activity. Furthermore, eugenol inhibits monoamine oxidase A (MAO-A) and may restore monoamines that are decreased in the brain of patients with depression. Thus, eugenol can be a good medicine for AD and depression. Here we suggest that eugenol and its analogs can be used also for other diseases of the central nervous system (CNS) including Parkinson’s disease (PD). This article reviews the previous investigations concerning effects of eugenol including its analogs on the CNS and describes perspectives of this highly potential compound.

Not only are methyl phenol compounds highly effective peroxynitrite scavengers, these compounds are highly concentrated in essential oils and can be inhaled directly into the part of the brain most affected by peroxynitrites–the hippocampus. One small-scale clinical trial with aromatherapy lasting 28 days saw some improvements in cognitive function in patients with dementia and especially those with Alzheimer’s disease. My own personal experience is that for late stage Alzheimer’s patients it takes several months and years to see major improvements. The point, however, is that by attacking the cause of the disease (peroxynitrites and not amyloid plaques per se), aromatherapy can not only stop the progression of Alzheimer’s disease, it can also partially reverse it.

Objective: Recently, the importance of non-pharmacological therapies for dementia has come to the fore. In the present study, we examined the curative effects of aromatherpay in dementia in 28 elderly people, 17 of whom had Alzheimer’s disease (AD).

Methods: After a control period of 28 days, aromatherapy was performed over the following 28 days, with a wash out period of another 28 days. Aromatherapy consisted of the use of rosemary and lemon essential oils in the morning, and lavender and orange in the evening. To determine the effects of aromatherpay, patients were evaluated using the Japanese version of the Gottfries, Brane, Steen scale (GBSS-J), Functional Assessment Staging of Alzheimer’s disease (FAST), a revised version of Hasegawa’s Dementia Scale (HDS-R), and the Touch Panel-type Dementia Assessment Scale (TDAS) four times: before the control period, after the control period, after aromatherpay, and after the washout period.

Results: All patients showed significant improvement in personal orientation related to cognitive function on both the GBSS-J and TDAS after therapy. In particular, patients with AD showed significant improvement in total TDAS scores. Result of routine laboratory tests showed no significant changes, suggesting that there were no side-effects associated with the use of aromatherapy. Results from Zarit’s score showed no significant changes, suggesting that caregivers had no effect on the improved patient scores seen in the other tests.

Conclusions: In conclusion, we found aromatherapy an efficacious non-pharmacological therapy for dementia. Aromatherapy may have some potential for improving cognitive function, especially in AD patients.

One can easily overcomplicated this disease or oversimplify it (in the case of the amyloid hypothesis), but there is often one causal factor (bacteria, virus, peroxynitrite, etc.) that explains the great majority of diseases and once you identify that factor and how to neutralize it, then you can successfully treat the disease.

I think we agree more than disagree. What I am giving you is the chain. High levels of glucose, high blood pressure due to high sodium levels, and Down Syndrome (because individuals with Down syndrome have an extra chromosome for the sodium myo-inositol co-transporter) lead to high levels of myo-inositol–the precursor molecule for amyloid plaques and peroxynitrites. Myo-inositol is converted into phosphatidylinositol 4,5 biphosphate. Phopsholipase C gamma and beta convert phosphatidyinositol 4,5 biphosphate into inositol 1,4,5 triphosphate which leads to calcium release from the endoplasmic reticulum and the activation of protein kinase C which in turn leads to the formation of amyloid plaques and peroxynitrtes. The protective link is the phoshpatidylinositol 3 kinase which converts phosphatidylinositol 4,5 biphosphate into phosphatidylinostil 3,4,5 biphosphate. The agents which inhibit PI3 kinase activity in order from greatest to least magnitude are presenilin gene mutations, the APOE4 gene, and bisphosphonate osteoporosis drugs such as Fosamax. Once you see the chain, then all the risk factors and putative protective measures for Alzheimer’s disease fall into place. Anything that inhibits the formation of peroxynitrites delays the onset of Alzheimer’s disease, anything that stops the subsequent formation of peroxynitrites stops the progression of the disease, anything that scavenges peroxynitrites and partially reverses their damage partially reverses the disease. We can continue to spend millions of more dollars to fund Alzheimer’s organizations and Alzheimer’s research centers, and we can sit by as pharmaceutical companies dangle one great hope after another and let themselves and some of their shareholders bask in the temporary uptick of their stocks or we can finally serve the people suffering from this disease and all the millions of others who lovingly take care of them despite all the pain, frustration, and anguish.

I have been trying to get some expert opinions on the peroxynitrites and Alzheimer’s disease. I believe in considering radical theories, especially over conventional theories that have failed to produce, but they have to be checked very carefully. I did get one suggestion to check the KEGG pathways (kegg.jp), which list these substances in one AD causation network model:

One response that I got was: “Citing one of many possible pathways WITHOUT providing evidence that the cited pathway actually is as important or more important than many other proposed pathways seems fundamentally empty. I’d ask the author to clearly indicate what is new and not new and also to provide supporting evidence that the impact of their favored pathway is equal to or greater than other pathways leading to Alzheimer’s. If their proposed pathways are not new they should at least provide a new combination of evidence supporting the significance of the path they propose.”

I don’t believe that the KEGG-Alzheimer diagram does justice to the peroxynitrites or the AICD. However, I worked for several years with Allan Butterfield and the late Bill Markesbery, who were major champions of the free radical theory of AD, and they worked with Tom Montine, another champion in this area. I really don’t think much of this concept. Free radicals are not necessarily bad (in fact, they are necessary for erections and are the reason that Viagra is so popular). Free radicals likely have a beneficial role in the formation of memory, specifically, for the destruction of unneeded synapses. The unique aspect of my opinion in this area is that the toxicity of the beta-amyloid, involving free-radicals, is necessary for the removal of unstimulated synapses in the course of neuroplasticity.

Though it does show the alpha-beta dichotomy of APP metabolism, the KEGG model does not show the synapse destroying aspect of APP-beta, nor the well-known critical role of the alpha-secretase products of APP in stimulating new synapse creation. Thus, the KEGG model provides no explanation for presence or the critical natural role of APP. Further, the KEGG model does not show the role of the AICD in the phosphorylation of tau, which is the critical event moving from APP metabolism to dementia. The phosporylation of tau is shown as a side-event, while the transformation of tau into PHFs and neuropil threads is the fundamental mechanism that is unique to Alzheimer’s disease, dementia pugilistica, and the Guamian-Parkinsonian dementia complex, and must be accounted for directly.

Another note about the KEGG pathway is that apoptosis – cell death – is essentially irrelevant to Alzheimer’s disease dementia. However, this is listed as the main adverse outcome. The KEGG conceptualization needs to be transcended before we try any more treatments for AD.

Another problem that has to be resolved is the role of APOE. The suggestion depicted in the KEGG model, which provides the well accepted LRP interaction, just does not seem to be adequate to explain its role in AD, especially with the failure of the amyloid-clearance concepts. APOE is well known to be a cholesterol chaperone and such a role in neuroplasticity and affecting membrane lipid make-up, seems much more reasonable, and could be related to the predisposition to Abeta42, which itself may not be the problem, but the AICD which is 2 amino acids shorter. Whether the AICD is the link to dementia is testable, and if so, means of controlling it would take center stage.

I will say that I appreciate the stimulation in helping to get some of these ideas in print.

I wish that I had seen the KEGG pathway for Alzheimer’s disease years before. It would have saved me lots of time. The bottom part of the chart is nearly perfect: the production of peroxynitrites at pathological levels (as occurs in Alzheimer’s disease) leads to protein oxidation, mitochondrial dysfunction, apoptosis, DNA damage, inflammation, and lipid peroxidation. My only qualm is that a few arrows are missing. An arrow should be drawn from peroxynitrites to tau hyperphosphorylation because the oxidation of g protein-coupled receptors and the nitration of tyrosine kinase receptors prevents the inactivation of GSK3 which is implicated in tau hyperphosphorylation. Peroxynitrite-mediated nitration then prevents the hyperphosphorlyated tau from being reconstituted into its normal form.

http://www.ncbi.nlm.nih.gov/pubmed/16816118

Another arrow should be drawn from peroxynitrites to amyloid aggregation as the nitration of the plaques contributes to their aggreagation.

http://www.ncbi.nlm.nih.gov/pubmed/21903077

Another arrow should be drawn from peroxynitrites to calpains as it is the nitration of NMDA receptors by peroxynitrites that leads to the influx of calcium that activates calpains that kills neurons. This process also leads to the release of glutamate that causes synaptic dysfunction.

The second is the role of phosphoilase C gamma (primarily activated by platelet derived growth factor receptor in the disease)

http://www.ncbi.nlm.nih.gov/pubmed/9804940

The third is the increased substrate (phosphatidylinositol 3,4 biphosphate for phosphospolipase C gamma and beta–activated by g proteins) to act upon due to the inhibition of the phosphatidylinistol 3 kinase.

As a side note, William Marksberry was one of the few scientists to respond to my hypothesis for this disease. He asked the critical question how do we know that the peroxynitrite scavengers found in several essential oils enter the brain in large enough concentrations to make a difference. He was a true gentleman.

I don’t now what role AICD (the amyloid precursor protein intracellular domain) plays in Alzheimer’s disease. All the chart says is modulation of gene expression and induction of apoptosis. As you suggest this isn’t very helpful. If you can tell me more about what role AICD plays in Alzheimer’s disease that would be helpful.

Otherwise, with the revisions suggested here, the chart explains almost all one needs to know about Alzheimer’s disease. Peroxynitrites lay behind almost every observed aspect of the disease and this explains why peroxynitrites scavengers have helped ameliorate the disease in animal models and in human clinical trials.

Just a side note William Marksberry was one of the few scientists ever to respond to me and his question was the most critical one: how do we know that the peroxynitrite scavengers contained in essential oils reach the brain in large enough concentrations to make a difference. He was a true gentleman.

A few apologies: William Markesbery. I am not a good editor, especially small print on a computer. Also you have provided a further explanation for the role that AICD may play in Alzheimer’s disease. Let me suggest that the arrow from peroxynitrites should also be pointing to AICD as peroxynitrite scavengers attenuate its toxicity. This would further explain why the removal of amyloid plaques is partially the wrong target.

http://www.ncbi.nlm.nih.gov/pubmed/11432978

Furthermore, conditioned media derived from CT105-treated astrocytes enhanced neurotoxicity and pretreatment with NO and peroxynitrite scavengers attenuated its toxicity. These suggest that CT-APP may participate in Alzheimer’s pathogenesis through MAPKs- and NF-kappaB-dependent astrocytosis and iNOS induction.

Please continue to share all of this information with your colleagues. The easiest way for them or you to reach me directly is through Alzconnected.com.

It will take me a little while to review all of the above points – I am far from a genius and I am certainly not a neurochemist or molecular biologist.

I did get one more response from a close colleague: “The initial claim is an exaggeration from an association to causation (“Since the mid-1990s it has been known that peroxynitrites are a principal cause of Alzheimerʼs disease”). Otherwise, I agree with …(the quotation from another colleague above)”.

I am glad you made comments on the KEGG pathways. The problem is that there are many possible pathways, and those that are in the causal chain or contribute to the causal chain each need to be firmly established…before any more exotic trials on Alzheimer patients are undertaken.

The AICD is just at the limit of my knowledge. However, it seems to me that the required sequence of beta to gamma secretase leads to two molecules, Abeta and AICD. One of them must be in the chain of causation. If we consider that the Abeta is substantially disproven, then the AICD must be the culprit. This makes more sense anyway since the issue is that something must get inside the cell – in this case inside the synapse far from the cell body and most DNA control. Something has to get inside the cell to over phosphorylate the tau to cause the dementia. I have been told that the AICD can phosphorylate tau, so that provides a necessary logical step. A significant component of Alzheimer causation is linked to APOE, so the role of that molecule must be further understood, likely leading to excess production of AICD or a harmful variant of AICD (the 2 amino-acids short). All of this is speculative and does not rule out other factors contributing to Alzheimer’s disease having a clock setting a few months or years earlier or later than it would otherwise occur, and even education seems to play such role.

I appreciate the Bach et al., 2001 reference: http://www.ncbi.nlm.nih.gov/pubmed/11432978 However, I want to re-emphasize my counterpoint – Abeta and AICD are not abnormal proteins or pathways. Some astrocyte response may even be important in the continual removal (millions per second under normal circumstances) of old synapses, and normal “immunologic” processes are also likely to be involved. I believe that it is the imbalance of the alpha and beta pathways, with the alpha pathway deteriorating more with age than the beta pathway, which must be considered. It is not that free radicals are bad, rather they are probably playing a normal important role; but they may contribute to the alpha-beta imbalance of the APP switch and its deleterious consequences with increasing age-related deterioration.

Thank you very much for your feedback and for that of your colleagues. I have largely been bouncing ideas off of a wall for past five years (with a few notable and happy exceptions). Peroxynitrites can have positive effects, but at the levels present in Alzheimer’s disease they are likely to be highly damaging (I like the description of peroxynitrites as floating mines). Peroxynitrite levels in Alzheimer’s disease have been linked to tau hyperphosphorylation, NMDA receptor activation, protein oxidation and nitration, lipid peroxidation, mitochondrial dysfunction, and perhaps DNA damage. What I did not know before was that the overproduction of the amyloid precursor protein as well as the aggregation of amyloid plaque itself play a role in the overproduction of peroxynitrites. Peroxynitrite scavengers may help in the treatment of Alzheimer’s disease because they limit the formation of peroxynitrites, scavenge peroxynitrites and repair part of their damage.

These results demonstrated that the memory protective effects of RA [Rosmarinic acid] in the neurotoxicity of Aβ25–35 is due to its scavenging of ONOO−, and that daily consumption of RA may protect against memory impairments observed in AD.

Abstract The inflammatory mediator peroxynitrite, when generated in excess, may damage cells by oxidizing and nitrating cellular components. Defense against this reactive species may be at the level of prevention of the formation of peroxynitrite, at the level of interception, or at the level of repair of damage caused by peroxynitrite. Several selenocompounds serve this purpose and include selenoproteins such as glutathione peroxidase (GPx), selenoprotein P and thioredoxin reductase, or low-molecular-weight substances such as ebselen. Further, flavonoids, such as (-)-epicatechin, which occurs in green tea or cocoa as monomer or in the form of oligomers, can contribute to cellular defense against peroxynitrite.

http://www.ncbi.nlm.nih.gov/pubmed/12676458

The critical questions are what peroxynitrite scavengers are most effective, at what doses, and with what side effects. I only have a partial answer to these questions at this point in time.

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